High Pressure Heat Treatment – Phase Transformation under Isostatic Pressure in HIP
Magnus Ahlfors, Alexander Angré, Dimitris Chasoglou, Linn Larssondownload PDF
Abstract. Modern HIP furnaces equipped with forced convection cooling enable very fast cooling rates under isostatic pressure. This does not only give shorter HIP cycles and increased productivity but also allows complete heat treatment cycles to be performed in the HIP unit. It has been shown in previous studies that extreme pressures of several thousand bar can push phase transformation towards longer times for the Fe-C system. The new URQ HIP cooling systems give the opportunity to investigate the impact of pressures up to 2000 bar on phase transformation time dependency. A 4340 steel was used in this study and a comparison of austenite phase transformation time at 100 bar and 1700 bar was performed. The study was performed by isothermal heat treatment of specimens for a specific time followed by quenching. To evaluate the influence of pressure on hardenability, the phase fractions were evaluated using grid method on SEM images. The study found significant influence of HIP pressure on the phase transformation kinetics of the material studied.
HIP, High Pressure Heat Treatment, URQ
Published online 2/11/2019, 8 pages
Copyright © 2019 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: Magnus Ahlfors, Alexander Angré, Dimitris Chasoglou, Linn Larsson, High Pressure Heat Treatment – Phase Transformation under Isostatic Pressure in HIP, Materials Research Proceedings, Vol. 10, pp 149-156, 2019
The article was published as article 21 of the book Hot Isostatic Pressing
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
 A. Åkerberg, The Difference Between URQ and U2RC, Proceedings HIP’14 11th International Conference on Hot Isostatic Pressing, Stockholm, Sweden, June 2014.
. A. Åkerberg, P. Östlund, Numerical Calculations of New Innovative Heat Treatment, Proceedings from HIP’14 the 11th International Conference on Hot Isostatic Pressing, Stockholm, Sweden, June 2014.
. A. Åkerberg, Temperature Accuracy in HIP Furnaces, Proceedings from HIP’14 the 11th International Conference on Hot Isostatic Pressing, Stockholm, Sweden, June 2014.
. A. Ahlfors, The Possibilities and Advantages with Heat Treatments in HIP, Proceedings from HIP’14 the 11th International Conference on Hot Isostatic Pressing, Stockholm, Sweden, June 2014.
. R. Larker, P. Rubin, Uniform Rapid Quenching Enables Austempering Heat Treatment in HIP, Proceedings from the 6th International Quenching and Control of Distortion Conference, Chicago, USA, September 2012.
. A. Weddeling, N. Wulbieter, W. Theisen, Densifying and Hardening of Martensitic Steel Powders in HIP Units Providing High Cooling Rate, Proceedings from EuroPM 2015, Reims, France, October 2015.
. É.R. Kuteliya, L.S. Pankratova and É.I. Estrin, Isothermal Transformation of Austenite under High Pressure, Translated from Metollovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 8-13, September, 1970.
 S.V. Radcliffe, M. Schatz and S.A. Kulin, The Effect of High Pressure on the Isothermal Transformation of Austenite in Iron-Carbon Alloys, Journal of the Iron and Steel Institute, pp143-153, February 1963.
 J.E. Hilliard and J.W. Cahn, The Effect of High Pressure on Transformation Rates, Progress in very high pressure research 1961, pp. 109-125, General Electric Research Laboratory, USA.
 American Society for Metals, Atlas of Isothermal and Cooling Transformation Diagrams, Metals Park Ohio, USA, 1977.